Field of the Invention
Prior to the instant invention it has been customary for box manufacturers to ship to their customers box blanks including blanks for box covers which the customer assembled on the customer's assembly machine. These assembly machines included mandrels, folding mechanisms, and glue applicators. A common mandrel is one which has straight sides and for special box covers, a special mandrel was utilized with cut-out portions to accommodate several thicknesses of tabs at the corner of a box cover for reinforcing same. When reinforcement tabs were not used, the straight mandrel operated satisfactorily but when floating corner reinforcement tabs as well as corner assembly tabs formed part of the box top blank, a special mandrel with offset or cut-out formations at the edges of the mandrel was required to obtain optimum results. In practice, the customer neglected to change from one mandrel to another with the result that the assembled box cover became unglued at the center and with neither the construction nor the appearance then being acceptable.